Miniaturised tri-band microstrip patch antenna design for radio and millimetre waves of 5G devices

This research presents an extremely small, cheap and simple structure of multiple bands antenna, where is the proposed design comprise square-slotted a microstrip patch antenna with triple bands of RF and mm-wave for 5G. The conducting material is a perfect electrical conductor on both sides. The antenna is printed on FR-4 lossy with a 3.9 of epsilon. Our tiny antenna has a size of 1.5357 x 1.5357 mm². First, the design parameters were calculated using formulas and then these were simulated by the CST MWS. The simulation results show the antenna performance at the RF band from 0 to 3.4096 GHz with 3.29 gain, a value of return loss S₁₁ and bandwidth of -13.229644 and 3.4096 GHz. The designed antenna works at the mm-wave band ranges 43.5-64 GHz with 3.49 gain, -42.419084 S₁₁ and 20.252 GHz BW. Our antenna can also operate at the mm-wave from 81-95 GHz with -22.269547 S₁₁, 4.52 gain, and 14.085 GHz BW. The small size and supported bandwidth of the designed antenna is suitable for thin and fast transmission devices.

1D and 2D phase gradient perforated dielectric reflective surfaces atmmWave

This paper presents the design of all dielectric non-absorptive phase gradient reflective surfaces that can be used to manipulate the reflected electromagnetic waves at millimeter-wave regime. Compared with a bare perfect electrical conductor reflector which obeys the classical Snell's law of reflection, the presented design can effectively alter both the shape and level of the backscattered energy and thus radar cross section (RCS) reduction is achieved in the specular direction. One- and two-dimensional phase gradient reflective dielectric surfaces of phase change about 72° across their apertures are designed and their ability to manipulate the reflected waves under normal incidence are investigated both by means of full-wave simulations and experimentally tested for validation. More than 6 dB of specular RCS reduction is achieved from about 66.5–78.2 GHz.

Low Radar Cross-section and Low Cost Dipole Antenna Reflector

This paper presents a method for reducing Radar CrossSection (RCS) of an increased gain metal backed dipole antenna. Numerical simulations were done and compared to a laboratory experiment. The results show that when a Perfect Electrical Conductor (PEC) is replaced by a Frequency Selective Surface (FSS), the antenna is still able to perform with the desired characteristics, but the RCS of the structure is greatly reduced out of band. The design of the FSS and the return loss, gain improvement, and RCS are presented for an antenna operating at 4.2GHz, and the results are compared with a conventional metal backed layout. Measurements show a good agreement with the simulations, and so the advantages on other structures from the reviewed literature are mentioned.

On the Accuracy of Asymptotic Solutions for TM Waves Diffracting on an Impedance Wedge

The contribution focuses on the accuracy of two asymptotic solutions aimed at representing the electromagnetic field scattered by penetrable wedges. One is a heuristic manipulation of the solution for the perfect electrical conductor, and the other one is a more rigorous coefficient based on approximate boundary conditions. The results presented here extend those proposed by other authors by illustrating the accuracy of such solutions at the edge of validity of the uniform theory of diffraction. In particular, they show that the heuristic formulation can be freely applied in similar conditions, while the other might not always lead to accurate predictions.

HELMHOLTZ INSTABILITY OF A VISCOUS COMPRESSIBLE PLASMA

An attempt has been made to discuss the Helmholtz instability of a viscous compressible plasma considered to be a perfect electrical conductor. Initially, the plasma is assumed to be in contact with a uniform magnetic field along a plane boundary that is parallel to the field and is assumed to flow with uniform velocity V0 perpendicular to the field. By using the normal mode technique, the amplitudes of the perturbed quantities are obtained. The conditions for the validity of the principle of exchange of stability and overstability are obtained also. Finally, the growth-rate curves for different values of the viscosity parameter λ′ have been drawn and it has been found that the effect of viscosity adds to the stability of the system.